Surface effect machine with pressure fluid cushion system



Aug- 6, 1968 L. DUTHloN ETAL 3,395,773

SURFACE EFFECT MACHINE WITH PRESSURE FLUID CUSHION SYSTEM 2 Sheets-Sheet 1 Filed April 12, 196e Fig.: 6

Aug. 6, 1968 L. DUTHION ETAL 3,395,773

SURFACE EFFECT MACHINE WITH PRESSURE FLUI SYSTEM D CUSHION Filed April 12, 1966 2 Sheets-Sheet 2 United States Patent O s claims. (l. 18o- 127) ABSTRACT OF THE DISCLOSURE A ground effect machine having a skirt depending from a platform and confining a pressure uid cushion formed against a bearing surface, said skirt being mounted for movement relative to sa-id platform, in the plane of motion thereof, from a mean relative position against a resilient return force, means being provided for damping said movement.

The present invention concerns surface effect machines comprising fluid cushions under pressure, and more particularly platforms comprising multiple cusions peripherally bounded by exible -skirts or rigid-walled bells projecting downwards beneath the platform.

It relates more especially to va mounting for these skirts or bells designed for relative translational displacement in the plane in which the platform moves, this mounting comprising combined means for translational guiding, returning to the original position, and oscillation-damping.

According to one form of embodiment of the present invention, the skirts or bells have a general shape of revolution about a vertical axis, and the combined means for mounting them are distributed in a substantially axially symmetrical arrangement.

In the appended drawings:

FIGURE 1 is a diagrammatic vertical part-section of a preferred form of embodiment of the present invention;

FIGURES 2 and 3 are similar views of two alternative embodiments;

FIGURE 4 is a horizontal diagrammatic section taken along the line IV-IV in FIGURE 3, showing the mounting of a skirt or bell;

FIGURE 5 illustrates on a larger scale a constructional detail of the embodiment of in FIGURE 3;

FIGURE 6 is a section similar to those in FIGURES 1 to 3 of another alternative of embodiment; and

FIGURE 7 -is a part-sectioned plan view from above of a skirt or 1bell element incorporated in this last embodiment.

The various embodiments illustrated in the drawings all have a platform 1 equipped at the bottom with ilexible skirts or rigid-walled bells 2 of generally frustoconical shape, yseparately fed with compressed air r other fluid under pressure via individual inlets 3, the whole forming an air-cushion vehicle of known type.

According to the present invention, the skirts or bells 2 are mounted below the platform 1 so as to be capable of relative translational displacement in the horizontal plane, that is to say parallel to the platform.

In the form of embodiment shown in FIGURE l, which is preferred because it is the lightest, the skirts or bells 2 are equipped with an upper frame 4 horizontally guided by means of a finger which is fast with the frame and engaged in a slot 6 in a support 7 fixed to the bottom of the platform 1. This guiding device imparts a practically fixed position as regards height to the frame 4, but allows it freedom of movement in a plane parallel to the 3,395,773 Patented Aug. 6, 1968 ICC platform 1. This frame is returned to a rest or mean position by springs 8 (see also FIGURE 4) acting in the radial direction between the frame 4 and a piece 9 fixed to the bottom of the platform 1. These springs, three in number and at 120 to one another in the example illustrated, are associated with dampers 10, which are also radial, interposed between the springs 8 and mounted on articulations between the frame 4 and fixed supports 11. The return springs 8 and dampers 10 as a whole are advantageously distributed in axially symetrical fashion with respect to the vertical axis of the skirts or bells, as shown in FIGURE 4.

A flexible peripheral seal 12 fixed to the frame 4 ensures that the liuid cushion is fluid-tight.

The platform which has just been described operates as a ground effect machine on air-cushions peripherally bounded by skirts or bells when the latter are fed with compressed air.

If a skirt or bell encounters an obstable, for example the crest yof a wave, when the platform is in motion, it receives an impact (and the greater the speed at which the vehicle is moving, the stronger the impact. The latter, instead of being transmitted directly to the vehicle, is transformed into relative displacement of the skirt or bell in the horizontal plane, which displacement is guided by the device 5-6-7 and takes place iagainst the action of the springs 8, which then return the skirt or bell to its original position, the oscillations involved being damped by the dampers 10.

Alternatively, the springs may be replaced by a peripheral chamber 13 (see FIGURE 2) interposed between the fra-me 4 and the platform 1, and receiving via feed pipes 14 uid at 1a pressure which is adjustable in motion. It will be noted that this chamber also ensures that the air-cushion is fluid-tight, and therefore plays the cornbined parts of the springs 8 and seals 12 in the foregoing form of embodiment.

In FIGURE 3, the air-cushion is no longer bounded at the top by the platform as before, but by a separate annular part 15 to the periphery of which the skirt or bell 2 is fixed, and which is linked to the conduit 3, which supplies fluid under pressure, by a flexible seal 16. This annular wall 15 comprises Ia projecting peripheral flange 28 to which is secured the mounting device of the invention, whereof the horizontal guiding means may be seen at 5-6-7, the return springs at 8, and the dampers at 10.

Between the upper face of the w-all 15 and the opposite lower face of the platform 1, there is an anti-friction labutment 17 which is illustrated in detail in FIGURE 5. This abutment comprises balls 18 trapped in a cage 19 and running both on the said upper face of the wall 15 and on the said opposite lower face of the platform 1.

It is not essential to use return springs such as` 8 in the forms of embodiment *so far described, and FIGURE 6 shows an alternative in which these springs are replaced by one or more blocks of elastic material 20 of annular shape surrounding an upper tubular extension 21 of the Wall 15, and disposed in a cylindrical recess 2-2 in the platform 1. Communication between the tubular extension 21 and the conduit which supplies fluid under prefssure is via la bellows 23, while the skirt or bell 2 is horizontally guided by a horizontal plate 24 fixed to this tubular extension at 25 and co-operating with a flange 26 on the recess 22.

In this last form -of embodiment, linings 27 having a high coefficient of friction are interposed between the upper face of the wall 15 and the opposite lower face of the platform 1 (see also FIGURE 7), for example of the type used as friction linings for braking motor vehicles.` This damps the periodic lateral movement, `the degree of damping varying with the load.

What is claimed is:

1. A movable body of the surface effect type having a support frame movable in a plane generally parallel to a surface along which said body is designed to move, and at least one enclosure confining a cush'on of iluii under pressure extending xbetween said frame and said surface, said enclosure having a mean position relative to said frame and being open at an end thereof adjacent said surface, wherein the improvement comprises a device for tting said enclosure to said frame, comprising guiding means interconnecting said enclosure and said frame and allowing relative translational displacement between said enclosure and frame parallel to said plane while Irestraining relative displacement thereof perpendicular to said plane, and means cooperating with said frame and said enclosure for exerting thereon a damped resilient action returning the enclosure to su'bstantially said mean position relative -to the frame.

2. Movable body as claimed in claim l, wherein said last mentioned means exert said damped resilient action in a plane substantially parallel to said surface.

3. Movable `body as claimed in claim 2, wherein said last mentioned means comprise separate springs and dampers extending in said plane.

4. Movable body as claimed in claim 2, wherein said enclosure admits of an axis of symmetry substantially perpendicular to said surface, and said translational guiding means and said damped resiient action means are distributed substantially symmetrically about said axis and operate in directions radiating from said axis and substantially perpendicular thereto.

5. Movable body as claimed in claim 2, wherein said last mentioned means comprise friction linings interposed between said enclosure and said frame, for damping relative oscillation thereof.

References Cited UNITED STATES PATENTS 3,185,240 5/1965 Eggington et al. 180-7 3,260,322 7/1966 Mackie 180-7 3,266,757 8/1966 Guienne 180-7 FOREIGN PATENTS 997,518 7/1965 Great Britain.

A. HARRY LEVY, Primary Examiner. 

